The power convertor all-digital control method based on model predictive control has grown rapidly in recent years. MPC (Model predictive control) is a mathematical-model-based control algorithm used for predicting the future response of object to be controlled. The algorithm comprises a value function defined according to the object to be controlled. By minimizing the value function, the optimal voltage vector is obtained for the algorithm during each sampling-period according to sampling-period prediction, and the optimal voltage vector is regarded as the interaction vector for the next period. MPC belongs to a non-linear control technique, and has fast transient response speed due to its no inclusion of linear controller and modulation algorithms. With the fast development of the micro processor and in-depth researching of the relevant techniques, MPC shows great advantages in the application of power electronics and motor driving fields.
MPC is a control algorithm for directly predicting and modulating current, and demands for a higher accuracy for the current to be detected. For eliminating interference, filtering process should be performed to the detected voltage and current signal prior sampling, but the filter will create signal delay while filtering high-frequency interference signal. As the MPC adopts circulation for optimization and non-constant-frequency control mode of outputting directly without modulation, the MPC has the advantage of fast transient response speed, but also has the disadvantages of high sampling frequency, and the system delay, thus affecting the operating performance. When the cut-off frequency of filter is low, signal filtering will suffer from some delay and produce variation between actual output value and set value of system, and further will impact the control effect. Therefore, it is necessary for us to develop a filter delay compensation method for MPC.